An image is viewed in connection with above display arrangements as being built up of a number of least resolution elements for the viewer, called picture elements. The image can be considered to consist of a distribution of these picture elements in two dimensions. Thus, the image can be viewed as a number of picture elements which are in each case defined by a picture element position given by two angle coordinates V.sub.1 and V.sub.2 relative to a reference direction from the viewer, and information in the form of intensity, color, polarization and so forth at each point in time, belonging to each picture element.
A system in which all picture elements synchronously emit picture information within a time interval which is shorter than the integration time .tau. of the human eye is perceived as a non-flickering image by the viewer. Such an image can be static, for example a photograph, or sequentially generated within the time .tau. by one or several picture elements emitting at the same time at a suitably high repetition rate, for example TV, to be perceived as a complete image by the eye.
Examples of such display arrangements already known are monitors, TV sets and PPI screens.,It is common to all these display arrangements that all the image information items, that is to say two angle distributions and picture element information items, which can subsequently contain information on intensity distribution, color, polarization and so forth, are generated in a display element arranged at one and the same place. The viewer is located at a distance from the display element which, depending on the type of display element, can vary between a distance of 0.5 meters and tens of meters and possibly even a greater distance.
In another type of display arrangement according to the first part, the display element is mounted in the immediate vicinity of the viewer. An example of the last-mentioned type of display arrangement is disclosed in SE B 8403706-8. In this case, the display element is mounted on a helmet carried by the viewer. The image is introduced into the view of the viewer with the aid of a semi-reflecting screen. In this case, too, all the picture information items are generated in a display element arranged at one and the same place.